1. Field of the Invention
The present invention relates to a holding structure of a hose clamp for positioning and holding the hose clamp on an outer periphery of an end portion of a hose. The hose clamp is used, for example, for connection of a fuel hose and a pipe in a motor vehicle.
2. Description of the Related Art
In a fuel piping of a motor vehicle, for example, in order to communicate between pipes, used is a fuel hose made of rubber or elastomer, including a gasoline fuel impermeable layer. A gasoline fuel path is formed between the pipes by fitting each end portion of the fuel hose to an outer periphery of the pipe.
In order to prevent the fuel hose from being detached from the pipe or to prevent leakage of the gasoline fuel at a joint region between the fuel hose and the pipe, the fuel hose is tightly fitted to the outer periphery of the pipe. However, different from the case of a resin tube, sufficient securing strength with respect to the pipe cannot be expected for the fuel hose itself that is made of rubber or elastomer. So, in a connecting structure typically employed, a hose clamp is fitted to an outer periphery of an end portion of the fuel hose, and the fuel hose is tighten and secured to the pipe by the hose clamp.
A hose clamp for firmly securing the fuel hose to the pipe comprises an annular clamp body, and a operating portion for diametrically contracting and expanding the clamp body. The operating portion is, for example, an operation screw. When this hose clamp is used, the clamp body in diametrically expanded state is preparedly fitted on a clamp mounting portion of an end portion of the hose while being positioned in a longitudinal direction of the hose, and then, the fuel hose with the hose clamp is fitted to the pipe. After that, the clamp body is diametrically contracted, for example, by rotating the operation screw with an electric driver or air driver, to tighten the fuel hose to the pipe. In this manner, connecting work may be carried out relatively easily.
Meanwhile, for example, in the hose clamp with an operation screw, it is necessary to rotate the hose clamp on the outer periphery of the end portion of the hose to locate the operation screw in a predetermined circumferential position when the operation screw is rotated, or to hold the hose clamp nonrotationally or irrotationally while the clamp body is diametrically contracted by rotating the operation screw. Thus, basically, connecting work requires both hands. However, in many cases, connecting work of the fuel hose and the pipe is done in a narrow engine compartment where parts are tightly packed and it is not allowed to do connecting work with using both hands freely. So, it bothers considerably an operator to tighten the hose clamp.
As for technique to eliminate such inconvenience, for example, Patent Document 1 discloses a holding structure of a hose clamp where a protrusion protruding in a longitudinal direction of the hose is provided on the clamp body, close to an operation screw, and a cut out portion is formed in an outer periphery of the end portion of the hose for receiving the protrusion. This allows to position the hose clamp in a circumferential direction with respect to the hose.
[Patent Document 1] JP-A, 4-194486
By the way, when the operation screw is rotated to diametrically contract the clamp body, both end portions of the clamp body relatively move in circumferentially opposite directions, and an overlapped region of the both end portions become longer gradually. So, in a holding structure where an anti-rotation engaging portion such as a protruding portion protruding in the longitudinal direction of the hose is formed on the clamp body, when the hose is tightened to the pipe by diametrically contracting the clamp body, the anti-rotation engaging portion tends to move so as to be displaced in the circumferential direction, and, for example, the anti-rotation engaging portion is pressed against a side wall of the cut out portion that receives the anti-rotation engaging portion. And, for example, when the side wall of the cut out portion is pressed firmly by the anti-rotation engaging portion, a portion of the hose or the hose body close to the side wall is deformed in a pressed direction, for example, radially outwardly. So, when the hose is tightened by the hose clamp, it could happen that sufficient sealing property between the hose and the pipe and stopper property of the hose with respect to the pipe cannot be secured. And, there is a fear that a crack caused in the side wall due to that the anti-rotation engaging portion is firmly pressed against the side wall, and thereby the sealing property or the like is lowered at an early stage.
Under the circumstances described above, it is an object of the present invention to provide a holding structure of a hose clamp where the hose clamp can be positioned and held in a circumferential direction with respect to a hose, without fear that securing and connecting property and sealing property between the hose and the pipe are not damaged.